1. Field of the Invention
The present invention relates generally to spindles for industrial machines and, more specifically, to a system for characterizing performance of a spindle used in an industrial machine.
2. Description of the Related Art
Industrial machines are frequently used in production environments, such as automotive vehicle production. It is especially important that these industrial machines provide reliable performance to avoid costly production delays due to machine malfunction. Machine spindle failures are a known contributor to machine downtime in a production facility. In the past, various methods have been used to increase the reliability, predictability and maintainability of the industrial machine. For example, the performance of a major component of the industrial machine, such as the spindle, has heretofore been evaluated within a test environment. These tests are typically performed under steady state conditions at a single operating speed, and could only verify a few characteristics of the spindle. While steady state testing may adequately characterize certain features of the spindle, it is not a sufficient indicator of long-term performance within a particular manufacturing environment.
In addition, environmental factors, such as vibration, temperature or coolants, may affect the performance and reliability of machine components. One approach is to monitor major machine components, in order to isolate a suspect component. However this approach is an inadequate indicator of long-term machine performance. Another approach is characterization of the machine components, structure, tooling and workpiece as an integral system. An example of such an approach is disclosed in commonly assigned U.S. Pat. No. 5,663,894, to Seth et al., xe2x80x9cSystem and Method For Machining Process Characterization Using Mechanical Signature Analysisxe2x80x9d the disclosure of which is hereby incorporated by reference. While this method works well, it does not provide for characterization of a particular component, such as a spindle, during the design phase for that component.
Thus, there is a need in the art for a spindle characterization system to test and measure the performance characteristics of a spindle under dynamic load and environmental conditions similar to those encountered in a production environment.
Accordingly, the present invention is a spindle characterization system for characterizing performance of a spindle used in an industrial machine. The spindle characterization system includes a machine base for providing a mounting and support surface and having a recessed portion. The spindle characterization system also includes a table base assembly for supporting the spindle disposed within the recess portion, and the table base assembly includes a table top and height adjustment mechanism for adjusting the height of the table top. The spindle characterization system further includes a spindle mounting mechanism having a top portion mounted to the spindle and a bottom portion mounted to the table top, and a spindle forcing assembly operatively connected to the spindle, and the spindle forcing assembly generates an axial load, radial load and a torque that is applied to the spindle to simulate a machine tool load. The spindle characterization facility includes a programmable controller operatively connected to the spindle forcing assembly for providing computerized numeric control, and a computer system in communication with the programmable controller.
One advantage of the present invention is that a spindle characterization system is provided that verifies the performance of a spindle under environmental conditions similar to a production environment. Another advantage of the present invention is that spindle characteristics are determined under oscillatory, radial, axial and torsional loads replicating machining loads occurring under actual machining operations. Still another advantage of the present invention is that numerous spindle characteristics, including dynamic stiffness, vibration, and thermal characteristics, can be analyzed under a variety of operating conditions. Yet another advantage of the present invention is that the analysis of the spindle""s characteristics can be used in enhancing the design of the spindle, to improve the operating performance of the spindle within a manufacturing environment. Still yet another advantage of the present invention is that performance verification of a spindle tested by the system enhances the robustness and reliability of spindle designs. A further advantage of the present invention is that the system includes a test stand base that has increased dynamic stiffness, so as not to influence the integrity of the spindle characterization.
Other features and advantages of the present invention will be readily appreciated, as the same becomes better understood, after reading the subsequent description taken in conjunction with the accompanying drawings.